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> AVX-512 will bring support for per-instruction static rounding to mainstream CPUs. That is a relief – this might actually make rounding modes usable. Unfortu
by StefanKarpinski 12y ago
> AVX-512 will bring support for per-instruction static rounding to mainstream CPUs.
That is a relief – this might actually make rounding modes usable. Unfortunately, it will only be usable on very new hardware, meaning that it's pretty hard to actually use in a language. Of course, as you point out, this is more of a hardware issue than a spec issue, but ultimately, I see one of the major responsibilities of a good spec to be ensuring that compliant hardware has all the primitives necessary to use features like rounding modes effectively. In my view, IEEE 754 has failed in this area. If a new version of the spec were to fix this, we would be in great shape – in 20 years.
- stephencanon 12y agoThe wonderful thing about very new hardware is that in a few years, it's mainstream hardware, and a few years later it's essentially all hardware. Unsurprisingly, it's the hardware manufacturers who block most new requirements on hardware that IEEE-754 might want to add. They very much want the committee to standardize existing practice, and short of reforming the membership rules, there's very little that could be done to prevent them from blocking changes.